排序方式: 共有18条查询结果,搜索用时 15 毫秒
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外型-1,4-氧桥-环己基-2,3-二羧酸晶体属单斜晶系,空间群为P2_1/n;晶胞参数为:α=5.594(3)A,b=11.178(7)A,c=14.675(11)A,β=91.46(5)°;Ζ=4.从直接法得到结构的初始模型,经块矩阵最小二乘修正后,最后的R值为0.072.在晶体中,分子间的O—H…O氢键将分子连接成层型氢键体系.使用自编的CNDO/2程序,计算得电子的能量、分子的总能量、偶极矩及各原子的电荷密度和净电荷. 相似文献
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用X射线单晶衍射方法测定了二乙酰丙酮氧钒与γ-甲基吡啶加合物VO(CH_3COCHCOCH_3)_2·NC_5H_4CH_3的晶体结构.晶体属空间群Cm(C_8~3),晶胞参数α=8.288(3)A,b=13.983(7)A,c=11.459(4)A,β=138.32(2)°,Ζ=2.由SYNTEX R3型四圆衍射仪收集了876个独立衍射数据,以Patterson重原子法导出粗结构,经块矩阵最小二乘法修正,最终得偏离因子R=0.093.所得结果与相应吡啶1∶1加合物的分子结构参数进行了对比,探讨了VO(acac)_2·L型这类化合物的结构化学特点,并对第六位配键的键型进行了分析和讨论. 相似文献
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Guoying Chee 《General Relativity and Gravitation》1998,30(12):1735-1748
Using the Dirac matrices the double self-dual and anti-self-dual structure of N=1 supergravity is discussed. It is shown that the (anti-)self-dual part of the curvature does not consist of the (anti-)self-dual part of the connection alone, and the (anti-)self-dual part of the Lagrangian quadratic in the curvature consists of the (anti-)self-dual part of the curvature alone only when the Lagrangian does not include torsion terms if the torsion of the spacetime does not vanish. Such a new Lagrangian is constructed. It includes no Einstein-Hilbert term but its self-dual part contains an Ashtekar term. 相似文献
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